Using the lizard, Anolis carolinensis, as a model system, I am investigating further the possible evolutionary origins of physiological and psychological influences upon reproductive behavior as well as how these behavioral controlling mechanisms adapt organisms to their environment. To this end, studies of the physiological control of species-typical behavior and of the stimulus control of hormone secretion are being conducted. Descriptive and analytic studies of the reproductive behavior and reproductive isolating mechanisms of sympatric species, including experiments on individual and species recognition, the role of the dewlap in interspecific communication, and display variation and sexual selection, will also be conducted in both the field and the laboratory. Research on the psychobiology of reproduction of snakes and turtles are also being conducted. Specifically, the hormonal regulation of male reproductive behavior in snakes is being investigated and the hormonally dependent male and female sex pheromones critical in the coordination of reproductive behavior will be isolated and characterized. Studies designed to test in the field hypotheses arising from laboratory research on pheromone communication in snakes and turtles are also planned.